Apple tweaked the naming scheme of its flagship OS with the macOS Sierra release, dropping the Mac OS X moniker for the shorter and simpler "macOS," which also fits better with the company's full lineup of operating systems that includes iOS, watchOS and tvOS.

macOS Sierra Officially Arrives in Fall 2016

macOS Sierra was introduced at Apple's 2016 Worldwide Developers Conference (WWDC) in early June 2016 alongside iOS 10, with official availability for both operating systems expected in the fall.

With the Sierra release of Mac OS, Apple continues its recent pattern of naming the latest OS based on a location in Apple's home state of California, a pattern that started with the Mavericks release. macOS Sierra is named for the Sierra (or Sierra Nevada) mountain range in California (and Nevada) that includes well-known locales like the Yosemite National Park and Lake Tahoe.

What's New in macOS Sierra?

macOS Sierra enhancements include the new Apple File System that now powers all of Apple's operating systems, Picture in Picture, iCloud Drive Desktop access, optimized storage features, a universal clipboard, desktop Tabs, enhanced Messages and Photos for Mac, Apple Music improvements and more.

macOS Sierra also brings over and integrates features from its other operating systems (iOS in particular), including Siri, the built-in "intelligent assistant" that offers voice control and assistance, Apple Pay, the company's mobile payments service and digital wallet app, and the ability to unlock your Mac with your Apple Watch.